Support for doing DNS at the proxy end. I've invented a new type of

[u/mdw/putty] / proxy.c

diff --git a/proxy.c b/proxy.c
index 3313abf..d43ad7b 100644 (file)
--- a/proxy.c
+++ b/proxy.c
@@ -14,6 +14,10 @@
 #include "network.h"
 #include "proxy.h"
 
+#define do_proxy_dns \
+    (cfg.proxy_dns == 2 || \
+        (cfg.proxy_dns == 1 && cfg.proxy_type != PROXY_SOCKS))
+
 /*
  * Call this when proxy negotiation is complete, so that this
  * socket can begin working normally.
@@ -240,6 +244,10 @@ static int plug_proxy_accepting (Plug p, void *sock)
     return plug_accepting(ps->plug, sock);
 }
 
+/*
+ * This function can accept a NULL pointer as `addr', in which case
+ * it will only check the host name.
+ */
 static int proxy_for_destination (SockAddr addr, char * hostname, int port)
 {
     int s = 0, e = 0;
@@ -252,13 +260,16 @@ static int proxy_for_destination (SockAddr addr, char * hostname, int port)
      * representations of `localhost'.
      */
     if (!cfg.even_proxy_localhost &&
-       (sk_hostname_is_local(hostname) || sk_address_is_local(addr)))
+       (sk_hostname_is_local(hostname) ||
+        (addr && sk_address_is_local(addr))))
        return 0;                      /* do not proxy */
 
     /* we want a string representation of the IP address for comparisons */
-    sk_getaddr(addr, hostip, 64);
+    if (addr) {
+       sk_getaddr(addr, hostip, 64);
+       hostip_len = strlen(hostip);
+    }
 
-    hostip_len = strlen(hostip);
     hostname_len = strlen(hostname);
 
     exclude_list = cfg.proxy_exclude_list;
@@ -285,8 +296,8 @@ static int proxy_for_destination (SockAddr addr, char * hostname, int port)
        if (exclude_list[s] == '*') {
            /* wildcard at beginning of entry */
 
-           if (strnicmp(hostip + hostip_len - (e - s - 1),
-                        exclude_list + s + 1, e - s - 1) == 0 ||
+           if ((addr && strnicmp(hostip + hostip_len - (e - s - 1),
+                                 exclude_list + s + 1, e - s - 1) == 0) ||
                strnicmp(hostname + hostname_len - (e - s - 1),
                         exclude_list + s + 1, e - s - 1) == 0)
                return 0; /* IP/hostname range excluded. do not use proxy. */
@@ -294,7 +305,7 @@ static int proxy_for_destination (SockAddr addr, char * hostname, int port)
        } else if (exclude_list[e-1] == '*') {
            /* wildcard at end of entry */
 
-           if (strnicmp(hostip, exclude_list + s, e - s - 1) == 0 ||
+           if ((addr && strnicmp(hostip, exclude_list + s, e - s - 1) == 0) ||
                strnicmp(hostname, exclude_list + s, e - s - 1) == 0)
                return 0; /* IP/hostname range excluded. do not use proxy. */
 
@@ -303,7 +314,7 @@ static int proxy_for_destination (SockAddr addr, char * hostname, int port)
             * match (ie. a specific IP)
             */
 
-           if (stricmp(hostip, exclude_list + s) == 0)
+           if (addr && stricmp(hostip, exclude_list + s) == 0)
                return 0; /* IP/hostname excluded. do not use proxy. */
            if (stricmp(hostname, exclude_list + s) == 0)
                return 0; /* IP/hostname excluded. do not use proxy. */
@@ -316,6 +327,17 @@ static int proxy_for_destination (SockAddr addr, char * hostname, int port)
     return 1;
 }
 
+SockAddr name_lookup(char *host, int port, char **canonicalname)
+{
+    if (cfg.proxy_type != PROXY_NONE &&
+       do_proxy_dns && proxy_for_destination(NULL, host, port)) {
+       *canonicalname = dupstr(host);
+       return sk_nonamelookup(host);
+    }
+
+    return sk_namelookup(host, canonicalname);
+}
+
 Socket new_connection(SockAddr addr, char *hostname,
                      int port, int privport,
                      int oobinline, int nodelay, Plug plug)
@@ -471,9 +493,9 @@ int proxy_http_negotiate (Proxy_Socket p, int change)
         * for this proxy method, it's just a simple HTTP
         * request
         */
-       char *buf, dest[64];
+       char *buf, dest[512];
 
-       sk_getaddr(p->remote_addr, dest, 64);
+       sk_getaddr(p->remote_addr, dest, lenof(dest));
 
        buf = dupprintf("CONNECT %s:%i HTTP/1.1\r\nHost: %s:%i\r\n",
                        dest, p->remote_port, dest, p->remote_port);
@@ -649,16 +671,25 @@ int proxy_socks4_negotiate (Proxy_Socket p, int change)
         *  user ID (variable length, null terminated string)
         */
 
-       int length;
-       char * command;
+       int length, type, namelen;
+       char *command, addr[4], hostname[512];
 
-       if (sk_addrtype(p->remote_addr) != ADDRTYPE_IPV4) {
+       type = sk_addrtype(p->remote_addr);
+       if (type == ADDRTYPE_IPV6) {
            plug_closing(p->plug, "Proxy error: SOCKS version 4 does"
                         " not support IPv6", PROXY_ERROR_GENERAL, 0);
            return 1;
+       } else if (type == ADDRTYPE_IPV4) {
+           namelen = 0;
+           sk_addrcopy(p->remote_addr, addr);
+       } else {                       /* type == ADDRTYPE_NAME */
+           sk_getaddr(p->remote_addr, hostname, lenof(hostname));
+           namelen = strlen(hostname) + 1;   /* include the NUL */
+           addr[0] = addr[1] = addr[2] = 0;
+           addr[3] = 1;
        }
 
-       length = strlen(cfg.proxy_username) + 9;
+       length = strlen(cfg.proxy_username) + namelen + 9;
        command = (char*) smalloc(length);
        strcpy(command + 8, cfg.proxy_username);
 
@@ -670,7 +701,11 @@ int proxy_socks4_negotiate (Proxy_Socket p, int change)
        command[3] = (char) p->remote_port & 0xff;
 
        /* address */
-       sk_addrcopy(p->remote_addr, command + 4);
+       memcpy(command + 4, addr, 4);
+
+       /* hostname */
+       memcpy(command + 8 + strlen(cfg.proxy_username) + 1,
+              hostname, namelen);
 
        sk_write(p->sub_socket, command, length);
        sfree(command);
@@ -939,24 +974,30 @@ int proxy_socks5_negotiate (Proxy_Socket p, int change)
             *  dest. port (2 bytes) [network order]
             */
 
-           char command[22];
+           char command[512];
            int len;
+           int type;
 
-           if (sk_addrtype(p->remote_addr) == ADDRTYPE_IPV4) {
-               len = 10;
+           type = sk_addrtype(p->remote_addr);
+           if (type == ADDRTYPE_IPV4) {
+               len = 10;              /* 4 hdr + 4 addr + 2 trailer */
                command[3] = 1; /* IPv4 */
-           } else {
-               len = 22;
+               sk_addrcopy(p->remote_addr, command+4);
+           } else if (type == ADDRTYPE_IPV6) {
+               len = 22;              /* 4 hdr + 16 addr + 2 trailer */
                command[3] = 4; /* IPv6 */
+               sk_addrcopy(p->remote_addr, command+4);
+           } else if (type == ADDRTYPE_NAME) {
+               command[3] = 3;
+               sk_getaddr(p->remote_addr, command+5, 256);
+               command[4] = strlen(command+5);
+               len = 7 + command[4];  /* 4 hdr, 1 len, N addr, 2 trailer */
            }
 
            command[0] = 5; /* version 5 */
            command[1] = 1; /* CONNECT command */
            command[2] = 0x00;
 
-           /* address */
-           sk_addrcopy(p->remote_addr, command+4);
-
            /* port */
            command[len-2] = (char) (p->remote_port >> 8) & 0xff;
            command[len-1] = (char) p->remote_port & 0xff;
@@ -1230,8 +1271,8 @@ int proxy_telnet_negotiate (Proxy_Socket p, int change)
                }
                else if (strnicmp(cfg.proxy_telnet_command + eo,
                                  "host", 4) == 0) {
-                   char dest[64];
-                   sk_getaddr(p->remote_addr, dest, 64);
+                   char dest[512];
+                   sk_getaddr(p->remote_addr, dest, lenof(dest));
                    sk_write(p->sub_socket, dest, strlen(dest));
                    eo += 4;
                }